1. Field of the Invention
The present invention relates to a next generation mobile communication system, and more particularly to a method of allocating a common packet channel (CPCH) in a next generation mobile communication system which can allocate a correct common packet channel (CPCH).
2. Discussion of the Related Art
Recently, ARIB and TTC in Japan, ETSI in Europe, T1 in U.S.A., and TTA in Korea have organized a Third Generation Partnership Project (3 GPP) to establish a technical standard for the mobile communication system of the next generation.
In the searches of the 3 GPP, the searches of UTRAN provide a definition and explanation of a transport channel and a physical channel.
Referring to the pertinent searches, a common packet channel (CPCH), which is one of the transport channels, is allocated between a base station (BS) and a user equipment (UE) to transport relatively long data from the UE to the BS through an Up-Link (UL). The Up-Link common packet channel (CPCH) is related to a dedicated channel (DCH), which is a channel for performing a close loop power control, while the DCH is mapped by a dedicated physical control channel (DPCCH). Such a CPCH is allocated to diverse UB by means of a random access manner.
The efficient allocation of the CPCH is currently recognized as being critical to avoiding a collision of the allocated channel when the CPCH is allocated in 3 GPP.
FIG. 1 illustrates a transporting manner of the common packet channel (CPCH) in the related art, and FIG. 2 illustrates a structure of a Down Link dedicated physical control channel (DL DPCCH) for the common packet channel (CPCH) in the related art.
The CPCH manner includes a CPCH Status Indicator Channel, which transports information on the availability and maximum transport rate of the CPCH provided by a base station, a Physical Common Packet Channel Access Preamble (PCPCH AP) section for requesting a use of a specific physical common packet channel (PCPCH), an AP-Acquisition indicator Channel (AICH) for transporting a response for the AP, a PCPCH Collision Detection Preamble (CD-P) section for a collision detection and a resolution, a collision Detection/Channel Assignment Indicator Channel for a response and the channel allocation to the CD-P, a PCPCH. Power Control Preamble (PC-P) section having a length of 0 or 8 slots for determining the transport power level before transporting the data, a DL Dedicated Physical Control Channel (DPCCH) for providing an inner loop power control, a PCPCH message section for transporting a user packet data as shown in FIG. 1. Here, the PCPCH message section is divided into a PCPCH message data section and a PCPCH message control section.
Meanwhile, the CPCH in 3 GPP operates in two modes. One is a UE channel selection method (UCSM), which selects the CPCH, and the other is a versatile channel assignment method (VCAM), which informs the UE after a Node B corresponding to the base station allocates the CPCH.
The CPCH Status Indicator Channel (CSICH) in the UCSM periodically transports information on availability of each CPCH.
The CSICH in VCAM periodically transports the information on the availability and the maximum transport rate of each CPCH.
The Access Preamble (AP), the Collision Detection Preamble (CDP), and AP-AICH transport one of the 16 signature sets having 16 lengths. The AP signature in the UCSM indicates a specific channel, i.e., a scrambling code of the specific channel.
AP signature in VCAM indicates a data transport rate desired by the UE. In the VCAM, specific channels are indicated by means of an AP signature, a signature of CD/CA-ICH, and a code.
Of the 16 signature sets having 16 lengths that are different from one another, 8 pieces are used for a response to the CD-P, while the other 8 pieces are used for a channel allocation.
CD/CA-ICH transports one of 8 signatures for the CD-P response in the UCSM method, while simultaneously transporting one of the 8 signatures for the CDOP response and one of the 8 signatures for the channel allocation in the VCAM. Accordingly, the two signatures are transported at the same time for different purposes according to the VCAM method.
FIG. 2 shows a structure of the DL Dedicated Physical Channel (DPCH) in the related art, which comprises a Dedicated Physical Control Channel (DPCCH) and a Dedicated Physical Data Channel (DPDCH). The DL DPCCH includes a Pilot, TPC, and TFCI, while the DL DPDCH includes a data channel.
FIGS. 3A-3C are timing sequence diagrams 10 explain a process of transporting the normal common packet channel in the related art.
FIGS. 3A-3C illustrate the process of transporting the common packet channel for a transport block set between a serving user radio network controller and a radio link control (SRNC-RLC) in a user equipment radio link control (UE RLC).
First, the UE performs the CPCH configuration for transporting the CPCH through a Radio Resource Control (RRC) procedure such as a radio bearer setup or a transport channel reconfiguration.
That is, the Medium Access Control (MAC) layer 2 of the UE receiving a request for transport of the data from the Radio Link Control (RLC) layer 1 of the UE through MAC-D-Data-REQ requests to layer 3 of the UE a status report of the CPCH through PHY-CPCH-Status-REQ. The status report is broadcasted through the CSICH using a channelization code such as an AP-AICH.
The L1 layer 3 of the UE receives the status report from the CSICH and transfers the same to the MAC layer 2 of the UE through PHY-CPCH-Status-CNF.
The MAC layer 2 of the UE selects a transport format for requesting CPCH access from the CSICH, and requests L1 layer 3 of the UE an access through PHY-Access-REQ alter delay of a specific length by performing a persistency check in accordance with the persistency value. At this stage, the L1 layer 3 of the UE forwards the AP with the first power P1. Next, the L1 layer 3 of the UE forwards the AP once again with the second power P2, which is higher than the first power P1 when a response for the AP is not received after elapse of a predetermined time.
An L1 layer 4 of the base station (Node B), which has received the AP from the L1 layer 3 of the UE, informs the received information to the RRC 5 of the base station (Node B), selects and transports the specific signature to the L1 layer 3 of the UE through AP-AICH. At this stage, the ACK message is forwarded according to the signature of the AP-AICH.
The L1 layer 3 of the UE, which has received the ACIC through AP-AICH, transports the CDP P to the L1 layer 4 of the base station (Node-B). The base station rode-B), which has received the CD-P selects the specific signature and transports the CD/CA-ICH.
The CD/CA-ICH in the UCSM only reply to the CD-P, while the CD/CA-ICH in the VCAM performs a reply and a channel allocation for the CD-P. At this time, the information on the channel allocation in the VCAM defines a scrambling code for the PC-P and the CPCH message section (the CPCH message data section, the CPCH message control section) in the L1 layer 3 of the UE.
The MAC layer 2 of the UE, which has received the PHY-Access-CNF front the L1 layer of the UE, selects the transport format of the CPCH and requests the data transport through PHY-Data-REQ after making a transport block set.
The L1 layer 3 of the UE, which has received PHY-Data-REQ, transports the message after establishing the transport power control preamble (PC-P) of 0 or 8 slot length. The data transport through the CPCH is continuously performed until all the data are transported, or to the end of the maximum frame length designated by the system.
The information on ACK or NAK of the RNC/RLC layer 8 is forwarded to the RLC layer 1 of the UE through the FACH,
FIGS. 3A-3C shows a process of transporting the CPCH for a transport block set, which is transported first from point A to point B, and a process of transporting the CPCH for each linked transport block set from point C to point D.
To solve at least the problems and disadvantages of the related art, an object of the present invention is to provide a method of allocating CPCH in a mobile communication system of next generation, by which the UE can transport data through correct utilization of the CPCH allocated by a base station
Additional advantages, objects, and features of the invention will be set forth in part in the following description and will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.
To achieve the above object in accordance with one aspect of the present invention, there is provided a method of allocating a CPCH in a mobile communication system of next generation, the method comprising the steps of: transporting at a base station (BS) a common packet channel control command (CCC) to a M through a DPCH when a power control preamble is transported from the UE; and transporting at the UE a common packet channel message to the base station through the common packet channel when the common packet channel control command is received within a predetermined time.